Pharmacology drugs for peptic ulcer Presentation.pptx

Drugs for peptic ulcer in detail

1. DRUGS FOR PEPTIC ULCER Done By: Roll no. 07,08,09,10

2. Classification

3. H2 Receptor blockers Mechanism of action Histamine stimulates specific receptors on stomach parietal cells to increase gastric acid secretion. These histamine receptors are classified as H2 receptors. H2 antagonists, or blockers, prevent the histamine activated release of gastric acid. H2 Receptor antagonist competitively block H2 receptors on parietal cell and inhibit gastric acid production. They are mainly effective in suppressing nocturnal acid secretion.

4. Cimetidine Pharmacokinetics It is the prototype drug and the first H2 blocker to be developed. It is adequately absorbed orally though bioavailability is 60-80%. T1/2 is 2-3 hrs. About 2/3 rd of the dose is excreted unchanged in urine and bile. It crosses placenta and blood brain barrier. DRUG INTERACTIONS: Cimetidine inhibits several cytochrome P450 isoenzymes and reduces hepatic blood flow. It inhibits the metabolism of many drugs causing it’s toxicity. Ex: Theophylline, Phenytoin, Carbamazepine. Antacids reduce absorption of all H2 blockers

5. Adverse effects Cimetidine has antiandrogenic action. High doses given for long periods have produced gynacomastia , loss of libido, incompetence, decrease in sperm count. Side effects like headache, dizziness, bowel upset, dry mouth are generally seen. Rapid or high dose IV injection can cause hallucinations, convulsions, bradycardia and cardiac arrythmia .

6. Ranitidine It is about 5 times more potent than cimetidine. It has longer duration of action (24hrs). No antiandrogenic action, no gynacomastia and does not increase prolactin secretion. It has lesser permeability to the brain. Lesser inhibition of hepatic metabolism of other drugs .

7. Famotidine It contains a thiazole ring and is 5-8 times more potent than Ranitidine. Exhibits longer duration of action despite an elimination of t1/2 of 2.5-3.5 hrs. No antiandrogenic action. Drug interactions and adverse effects are minimal

8. Roxatidine ROXATIDINE It is two times more potent than Ranitidine and longer acting. It has no antiandrogenic or cytochrome P450 inhibitory action. LAFUTIDINE It enhances NO production, improve gastric mucosal blood flow, mucus production and somatostatin release. Lafutidine is indicated in dyspepsia, peptic ulcer, GERD.

9. Therapeutic uses Peptic ulcer H2 blockers produce symptomatic relief within days and ulcer healing within weeks H. Pylori – associated ulcer: H2 blockers can be used along with antimicrobial agents to treat H. Pylori infection Stress ulcer are commonly seen in patients with severe medical or surgical illness. Intravenous H2 blockers are used to prevent stress related ulcer and bleeding. NSAID’s Induced ulcer: H2 blockers can be used but they are less effective than proton pump inhibitors. 2. GERD H2 blockers are indicated only in mild or stage 1 cases of GERD.

10. 3. ZOLLINGER-ELLISON SYNDROME In Z-E syndrome, surgery is the definitive therapy Proton pump inhibitors or H2 blockers are used to control hypersecretion of acid. 4. PROPHYLAXIS OF ASPIRATION PNEUMONIA H2 Blockers given pre operatively reduce the risk of aspiration of acidic gastric content during anaesthesia and surgery .